1. Field of the Invention
The present invention relates to an image-forming apparatus having a plurality of processing modules including one or more processing modules with respect to an image-forming processing and one or more processing modules with respect to post processing.
2. Description of the Related Art
Hitherto, an image-forming apparatus has been provided, in which post-processing devices such as a finisher are connected to the image-forming apparatus such as a copying machine enabling various kinds of post-processing demanded by users such as bundle discharge processing, stitching processing, folding processing, and bookbinding processing to be performed. In order to enable these entire kinds of post-processing required from the users to be performed in one system, a plurality of post-processing devices executing each dedicated processing are sequentially connected to the image-forming apparatus.
In such an image-forming apparatus, there are provided covers arranged on outer casings of the image-forming apparatus and post-processing devices, the covers being openable/closable so that a worker such as a user or a service personnel can access inside of the apparatus in the case of jamming-recovery action performed by the user and maintenance carried out by the service personnel, such as part replacement, adjustment, and cleaning.
A conventional image-forming apparatus example having the above-mentioned covers provided thereon will be described with reference to FIG. 30. FIG. 30 is a longitudinal sectional view of an essential part of a conventional image-forming apparatus.
The conventional image-forming apparatus, as shown in FIG. 30, is provided with a printer 300 for forming images on a sheet by an electrophotographic process. The printer 300 includes an exposure control unit 110 having a polygon mirror 110a, a photosensitive drum 111, a development device 113, a transfer unit 116, a fixing unit 117, a flapper 121, a discharge roller 118, an inversing path 122, a double-sided transfer path 124, two cassettes 114 and 115, and a manual paper feeder 125. From the cassettes 114 and 115, the manual paper feeder 125, or the double-sided transfer path 124, a sheet is supplied and transferred between the photosensitive drum 111 and the transfer unit 116. Developed images formed on the photosensitive drum 111 are transferred on a sheet, which is supplied by the transfer unit 116, and the developed images transferred on the sheet are fused on the sheet in the fixing unit 117.
In the image-forming apparatus, covers 351 are provided to be openable/closable and accessible from the outside to the entire of a plurality of transfer paths for transferring sheets (including sheet-transferring paths from the cassettes 114 and 115 to the photosensitive drum 111, a transfer path for discharging sheets, the reversing path 122, and the double-sided transfer path 124). These covers 351 cannot be opened during normal image-forming operation, and are to be opened for jamming recovery action or maintenance during a down time. Therefore, if the cover 351 is opened during the image-forming operation, it is determined that an abnormal state is generated so as to stop the entire operation.
Also, to such a post-processing device disclosed in U.S. Pat. No. 6,330,422, a cover similar to that for the image-forming apparatus is provided.
However, in the image-forming apparatus described above, not all of sheets pass through the same transfer path, and depending on the setting by a user, the transfer path may differ in each sheet. For example, the sheet transfer path in a single-sided mode is different from that in a double-sided mode in the image-forming apparatus while in the post-processing device, the sheet transfer path differs among a stitching mode, a folding mode, and a bookbinding mode. Accordingly, the number of sheets passing through the transfer path is different from each other, resulting in different maintenance timing in each device or transfer path of the system. If part replacement is exemplified among kinds of maintenance, since each part itself has a different endurance limit to the number of sheets, even the number of passing through sheets is the same, maintenance timing is different in each device or each transfer path of the system.
Therefore, in a conventional structure of the system, opening the cover for maintenance stops the entire system. In the system having post-processing devices sequentially connected thereto, maintenance of the post-processing device can be carried out without stopping the entire system. In this case, however, it is necessary to remove the device for maintenance out of the system as well as to initialize the control unit for controlling the entire system again so as to recognize the connected post-processing device.
In such a manner, in a conventional image-forming apparatus, maintenance must be carried out with various timings, which produces the-shutdown of the entire system or the dismounting of the device and re-initialization involved therein. As a result, the maintenance reduces the system operating time, i.e., the system service factor.